After Robin Williams’ wife revealed that the actor had been in the early stages of Parkinson’s Disease before his death, actor Michael J. Fox tweeted his shock over the news.

Robin Williams was in the beginning stages of Parkinson’s Disease when he tragically committed suicide on Aug. 11 at the age of 63. Robin’s friend and fellow actor, Michael J. Fox, 53, who also has the illness, was “stunned” to learn of the actor’s diagnosis.

Robin’s wife, Susan Schneider, released a heartbreaking statement on Aug. 14 that detailed the late comedian’s “battles of depression, anxiety as well as early stages of Parkinson’s Disease, which he was not yet ready to share publicly.”

Before learning the news of Robin’s secret struggle, Michael called Robin a “genius” and a “gentle soul” in an emotional tweet. “Famously kind, ferociously funny, a genius and a gentle soul. What a loss. #RobinWilliams,” he wrote. Michael is just one of countless other actors and comedians who’ve paid tribute to the late actor.

Robin Williams: His Family Grieves Over Their Tragic Loss

Robin’s family continues to mourn the devastating loss of the Oscar-winning actor. The actor’s ex-wife, Marsha Garces, released a sad statement about her former husband’s death.

“My heart is split wide open and scattered over the planet with all of you. Please remember the gentle, loving, generous – and yes, brilliant and funny – man that was Robin Williams,” Marsha said. “My arms are wrapped around our children as we attempt to grapple with celebrating the man we love, while dealing with this immeasurable loss.”

Robin’s 25-year-old daughter, Zelda Williams, wrote a moving ode to her dad on her Tumblr page. She said that her father was the “kindest, most generous, gentlest souls” and the “entire world is forever a little darker” with his absence.

Robin was photographed out at a local Bay Area art gallery on Aug. 9, two days before his death. The actor has four films that will be released posthumously.

Our thoughts and prayers continue to go out to Robin’s family and friends during this difficult time.